NEIL GERSHENFELD is a Professor at the Massachusetts Institute of Technology and the head of MIT’s Center for Bits and Atoms.

A new digital revolution is coming, this time in fabrication. It draws on the same insights that led to the earlier digitizations of communication and computation, but now what is being programmed is the physical world rather than the virtual one. Digital fabrication will allow individuals to design and produce tangible objects on demand, wherever and whenever they need them. Widespread access to these technologies will challenge traditional models of business, aid, and education.

The roots of the revolution date back to 1952, when researchers at the Massachusetts Institute of Technology (MIT) wired an early digital computer to a milling machine, creating the first numerically controlled machine tool. By using a computer program instead of a machinist to turn the screws that moved the metal stock, the researchers were able to produce aircraft components with shapes that were more complex than could be made by hand. From that first revolving end mill, all sorts of cutting tools have been mounted on computer-controlled platforms, including jets of water carrying abrasives that can cut through hard materials, lasers that can quickly carve fine features, and slender electrically charged wires that can make long thin cuts.

<i>A printed pig. (Makerbot / flickr)</i></br>
"A new digital revolution is coming, this time in fabrication. It draws on the same insights that led to the earlier digitizations of communication and computation, but now what is being programmed is the physical world rather than the virtual one. Digital fabrication will allow individuals to design and produce tangible objects on demand, wherever and whenever they need them. Widespread access to these technologies will challenge traditional models of business, foreign aid, and education."

<i>Parts for a 3-D printer. (Zach Zupancic / flickr)</i></br>"The next-generation digital fabrication products on the market now, such as the RepRap, the MakerBot, the Ultimaker, the Pop-Fab, and the MTM Snap, sell for thousands of dollars assembled or hundreds of dollars as parts. Unlike the digital fabrication tools that came before them, these tools have plans that are typically freely shared, so that those who own the tools (like those who owned the hobbyist computers) can not only use them but also make more of them and modify them."

<i>A Starfleet replicator in action. (Star Trek: The Next Generation)</i></br>"Eventually, integrated personal digital fabricators comparable to the personal computer do not yet exist, but they will. Personal fabrication has already been around for years as a science-fiction staple. When the crew of the TV series Star Trek: The Next Generation was confronted by a particularly challenging plot development, they could use the onboard replicator to make whatever they needed. Scientists at a number of labs (including mine) are now working on the real thing, developing processes that can place individual atoms and molecules into whatever structure they want."

<i>A student demonstrates a dress built to defend the wearer's personal space. (MIT Center for Bits and Atoms)</i></br>"I first appreciated the parallel between personal computing and personal fabrication when I taught a class called "How to Make (almost) Anything" at MIT's Center for Bits and Atoms, which I direct. ...Each student later completed a semester-long project. One made an alarm clock that the groggy owner would have to wrestle with to prove that he or she was awake. Another made a dress fitted with sensors and motorized spine-like structures that could defend the wearer's personal space. The students were answering a question that I had not: What is digital fabrication good for? As it turns out, the "killer app" in digital fabrication, as in computing, is personalization, producing products for a market of one person."

<i>A warning. (Sorta Porta / flickr)</i></br>"Are there dangers to this sort of technology? In 1986, the engineer Eric Drexler, whose doctoral thesis at MIT was the first in molecular nanotechnology, wrote about what he called "gray goo," a doomsday scenario in which a self-reproducing system multiplies out of control, spreads over the earth, and consumes all its resources."

<i>3-D printed lower reciever of an AR-15 rifle. (3Dprinting / flickr)</i></br>
"A more immediate threat is that digital fabrication could be used to produce weapons of individual destruction. An amateur gunsmith has already used a 3-D printer to make the lower receiver of a semiautomatic rifle, the AR-15. This heavily regulated part holds the bullets and carries the gun's serial number."

<i>A summer camper at a fab lab in Chicago. (Opacity / flickr)</i></br>
"But communities should not fear or ignore digital fabrication. Better ways to build things can help build better communities... And by bringing welcoming environments to innovators wherever they are, this digital revolution will make it possible to harness a larger fraction of the planet's brainpower."

Today, numerically controlled machines touch almost every commercial product, whether directly (producing everything from laptop cases to jet engines) or indirectly (producing the tools that mold and stamp mass-produced goods). And yet all these modern descendants of the first numerically controlled machine tool share its original limitation: they can cut, but they cannot reach internal structures. This means, for example, that the axle of a wheel must be manufactured separately from the bearing it passes through.

In the 1980s, however, computer-controlled fabrication processes that added rather than removed material (called additive manufacturing) came on the market. Thanks to 3-D printing, a bearing and an axle could be built by the same machine at the same time. A range of 3-D printing processes are now available, including thermally fusing plastic filaments, using ultraviolet light to cross-link polymer resins, depositing adhesive